Shuttle cargo to study cosmos

The somewhat-overshadowed star of the space shuttle Endeavour's last voyage is a 15,251-pound experiment that scientists hope will solve some of the mysteries of the universe.

The Alpha Magnetic Spectrometer-2 resembles a giant spool of metal, 15 feet wide and almost as tall. From its perch atop the International Space Station, the AMS, as it's known, will continually sift space particles, analyze them and send the information through the space station to scientists on Earth.

"It's a pretty sophisticated payload, in development 16 years," shuttle commander Mark Kelly said during a NASA news conference in March. "We're pretty excited for what this means for science aboard the ISS and for real science on the origin of the universe," Kelly said.

Despite the advances made in space, scientists have many questions about the universe. For instance, scientists believe galaxies made up of stars, gas and dust have much more mass than is visible. Astronomers theorize the undetectable mass is dark matter, which exerts an incredible gravitational pull and emits no light. But scientists have never been able to detect a particle of dark matter. The AMS' ability to study space particles may help scientists detect such matter.

Here's how the more than $1 billion AMS works: Space particles pass into the instrument, where detectors analyze their mass, energy and how fast they move. A magnet within the AMS, the largest magnet ever used in space, will cause the particle to curve in one direction or another, with the goal of telling scientists whether the particle is matter or antimatter. Matter is essentially anything that has mass. Antimatter is more mysterious.

Scientists have long been obsessed with finding and studying antimatter. The big-bang theory suggests our universe was created in a big explosion. Matter and antimatter should have been created equally, but scientists have had difficulty finding antimatter. One theory is that a parallel universe of antimatter exists and is made up of particles with electrical and magnetic components that are opposite that of regular particles.

No one is sure what the AMS will discover, not even the instrument's lead scientist, Samuel Ting, a professor at the Massachusetts Institute of Technology.

"Expert opinion is based on existing knowledge. Discovery breaks down existing knowledge," Ting said during a speech last year at NASA's Kennedy Space Center.

In addition to carrying the AMS, the Endeavour will haul spare parts to stock the space station. The launch Friday will mark the Endeavour's last scheduled flight and the second-to-last flight of NASA's 30-year-old space-shuttle program. NASA is retiring the shuttles to devote resources to other programs, including possibly sending humans to an asteroid and then Mars. The final shuttle, the Atlantis, is set for launch in June.